My first Pinecest
by ieatsmiledip
Summary: Dipper realizes Mabel is perfect for him. He wants her, no, needs her. Needs her so much that he is willing to make a deal with a demon... P.S: If you don't like Gravity Falls shippings, DON'T ******* READ IT. Also, it's M for a reason. Thank you. P.P.S: All credit to whoever drew the cover image, I just found it and liked it.
1. Chapter 1

**Author's note: Hi, ieatsmiledip here! I am so glad for the support and I SINCERELY apologize for my short chapters, plot that starts off in this chapter really suddenly, and my imperfect writing. Feel free to PM me and comment/follow, and I'm sorry this is such a long note. Enjoy!**

Dipper opened his groggy eyes and looked over at Mabel. _Had she always been this pretty?_ The sun glinted off her hair as she leaned against the rear window of the Stanleymobile, exhausted after the long drive from Piedmont. _Shut up, brain! You know she's off limits. I mean she's my sister. That's gross, right?_ The question mark was still lingering in his mind when Mabel began to stir.

"Hey guys!" Mabel cheerfully said, her voice a little gruff from sleep.

"G'mornin, Mabel," replied Grunkle Stan and Dipper at the same time.

"How much longer 'till we get to the shack?" she asked. "40 minutes at the most, probably more like 30 minutes now," said Grunkle Stan.

"In that case I think I'll go back to sleep," Mabel said with a yawn. She leaned her head over and rested it on Dipper's shoulder. Dipper tensed up and started to sweat. He inhaled the sweet, bubblegum aroma of her hair and ever-so-slowly lowered his gaze to Mabel's chest, whose twin residents had grown considerably over the past two summers.

 _Damn!_ Dipper thought to himself as he sat, still, stiff, and sweaty. _Since when has Mabel been so hot?_ Her face, her hair, her breasts, even her usually aggravating constantly upbeat attitude was attractive to the hormonal teen.

"Hey kid? Why you sweatin' so much?" Grunkle Stan asked, interrupting Dipper's train of thought.

"Uh, no reason!" Dipper quickly replied. Maybe a little to quickly, though.

"Yeah, whateva ya say, kid," Grunkle Stan said, only slightly suspicious.

 _Phew!_ Dipper thought. _That would have been soooo awkward_.

 **Later that night, Dipper and Mabel's room.**

Dipper lay awake, thinking. He had managed to keep his mind off Mabel's newfound hotness for the rest of the day, but now he couldn't get her out of his mind. He thought of every positive quality she had: she was funny, nice, caring, attractive, smelled nice, and knew everything about him. _The perfect girl. Except for the fact that she's my sister_.

"But we can get over that, can't we," somebody said with a hint of a smile in their voice.

"Who's there?" Dipper said, a sudden fear struck into his voice.

"I think you know who it is, Pine Tree."

"Bill!?" Dipper whisper yelled.

"You guessed it, Pine Tree," said Bill as the dream demon materialized next to Dipper's bed. "And I think that I have a deal that will interest you," Bill said with a hint of joy and excitement in his voice. "Interest you very much!"


	2. Chapter 2

Dipper looked at the dark outline of Bill suspiciously. "What kind of deal do you have in mind? he asked.

"Oh, just a... personal favor," Bill said, wringing his hands, embarrassed and excited. "You see, it gets pretty lonely being an all powerful four-dimensional being and I was hoping that"

"You want to fuck me, don't you, Bill?" Dipper interrupted.

"Well, yes, as a matter of fact. You'll get something too, of course. I've seen what you want, and I think I can provide the love of your sister. And in return, I get to try the human reproductive process" Bill said, outlining the deal. "Whaddya say," he said, sticking out a hand engulfed in blue flame. Dipper thought about it. He wanted Mabel so bad. No, needed her. His life wouldn't be complete without her being his, and only his.

"It's a deal, Bill!" Dipper said, grabbing Bill's outstretched hand and giving it a quick shake. The flames spread from Cipher's hand to Dipper's, sealing the deal.

"I'll be back to collect my end of the bargain tomorrow night!" Bill laughed as he faded away. The room faded to white as Dipper woke up with a gasp. He checked the time; it was now about seven in the morning. Dipper smiled to himself, thinking about his plans of what to do with Mabel when she would finally be his.


	3. Chapter 3

"Okay kids, time to hit the hay!" Grunkle Stan yelled from downstairs, where he was watching a rerun of his favorite movie, The Duchess Approves. Dipper smiled to himself, glad to be finally fulfilling his end of the deal. Pretty soon, Mabel would be all his. He was barely able to change into his pajamas and brush his teeth, he was so jittery with excitement. At last, Dipper and Mabel were in bed.

"G'night, brobro!" Mabel called from across the room.

"Goodnight Mabel!" Dipper called, a smile in his voice. He closed his eyes and drifted off to sleep, ready to meet Bill in the Mindscape.

 **Dipper's Mindscape**

Dipper seemed to open his eyes to find a dull white room, about fifteen feet by fifteen feet square. Light seemed to emanate from the ceiling, but there was no light fixtures. The only thing in the room was Bill.

"Hey Pine Tree!" said the human form Bill had taken, a naked, dark skinned man with yellow hair and an eye-patch. Dipper estimated his form to be about 20, but he knew the demon was actually older than the known universe.

"Let's get this over with," Dipper intoned, implying he was bored and ready to be with Mabel.

"Ah, look up Pine Tree. I know what you'll enjoy!" Bill snapped his fingers, and Dipper was naked with his hands and feet tied together in front of him, exposing his tight virgin asshole. Bill walked up, and a glowing, blue paddle of light appeared in his hand. He began to spank Dipper's perfect bubble ass, while Dipper screamed in pleasure and pain. "Have you had enough yet?" Bill inquired seductively.

"Ye-Yes!" Dipper replied.

"You will call me master!" Bill screamed, spanking Dipper so hard he began to cry.

"Y-y-yes master!"

"That's better, slave. Now accept my girth!" Bill snarled. He turned and stuck his 9 inch, pulsating penis in the boy's unprepared ass, causing Dipper to scream in pain. "Don't worry, slave. It'll be better." Dipper just whimpered in response. But Bill wasn't lying. As Bill slammed his dick into Dipper's prostate, Dipper began to feel better and better. All to soon, he felt the familiar release of orgasm coming on.

"I'm gonna cum!" Dipper gasped.

"Me too!" Bill moaned. "Ahhhooohh!" They moaned together as they both came, Dipper on the ground of his mindscape and Bill inside of Dipper. Bill slowly pulled out and took a look at his hot seed slowly dripping out of Dipper's stretched asshole. He smiled, observing his work, and took a swipe with his finger in order to taste his handiwork. When he was finished, he snapped his fingers. With a pop, Dipper was back in his pajamas and Bill was back in triangle form.

"Hey, thanks Pine Tree. Expect your part of the deal any time." Bill began to fade away, but Dipper quickly stopped him by grabbing on to one of Bill's corners. "Whaddya want, Pine Tree? Missed me already?"

"No, Bill, but about what just went down... if you're in the neighborhood, just, you know, stop by or something," Dipper said with a blush. "Oki Doki, Pine Tree. I think I'll take that offer sometime," Bill said with a smile. Bill faded to black, and Dipper closed his eyes to gather his thoughts.

Dipper sat up with a gasp. He looked over to check the time, finding it was seven o'clock. Dipper smiled in his mind, thinking of what was to come.


	4. Chapter 4

It had been only three days since the deal with Bill, but already Dipper was seeing results. Not huge results, but they were there. Just this morning, he had caught her staring at him out of the corner of his eye. _Not much longer!_ he thought with a slight smile. _She'll need me just as much as I need her soon._

 ***Mabel's POV* A/N: I'll try not to do this too often, I know it gets annoying.**

"Dear Diary Thingy,

Three days ago, the craziest thing happened. My brobro turned, like, wow-wow. I've started to stare at him, but I can't help it. Whenever I think about him, my brain turns wack-a-doodle craycray. Recently, I've been thinking about what it would be like to kiss him. Even though it would be wrong, it would just be so... right. I've just been unable to stop thinking about that soft hair, green eyes, luscious lips, and how much I just want him to"

 _Oh no. Oh, nonono. You can't want him to fuck you, that's wrong!_ she thought to herself, already knowing that the forbidden thought was true. She sat up from her bed, abandoning her diary mid sentence. She had slammed it shut and started to quickly stuff it under her mattress when Dipper walked in the open door to their shared bedroom. "Heeey, brobro! Um, how's it going?" Mabel said awkwardly.

"Mabel, you're as white as a sheet! Did you see somethin' paranormal?" Dipper asked, seeming genuinely concerned.

"Nope, nothin'!" Mabel said, obviously trying to be nonchalant.

"Hey kids! Who wants to go camping!" Stan yelled from downstairs.

"We do!" Dipper and Mabel shouted together.

"Phew! Saved by the Stan!" Mabel whispered under her breath. But she was thinking. _Maybe this camping trip could be her chance to get closer to Dipper!_ She withered with joy just thinking about it. She jumped off her bed and grabbed an empty suitcase from the closet. She began dumping all her favorite sweaters and leggings in the main pocket. She zipped up her suitcase, knowing that Dipper would pack more than enough gear for the both of them. She dragged her suitcase down the steps and through the living room, pausing only to tap a hello to Grunkle Stan's axolotl and her lobster through the fishtank glass. She arrived at the front door just as Dipper was coming back in. "Could you carry my bag to the car, please, broski?" she ad-libbed, just wanting an excuse to see his newly well defined muscles in action.

"Sure thing, M'Lady!" Dipper said with a smirk as he took the bag from Mabel's hand. What he didn't know (but gleefully suspected), however, was that Mabel's heart had fluttered at him calling her "M'Lady." _I've got to tell him how I feel._ _In fact, I'll do it on this trip!_ Mabel promised herself. _Because I can't live without him. But what if he hates me afterward?_ But Mabel knew it was a risk she would just have to take.


	5. Chapter 5

**Authors Note: I am so sorry this took so long! My life has been a whirlwind of work, midterms, etc. I hope you like my story! And as always, feel free to follow, review, and P.M. me!**

Mabel was sitting in the back of the Stanleymobile with hers and Grunkle Stan's stuff, and she could hear Dipper's belongings occasionally thumping into one of the walls in the trunk. They had been driving for two hours, trying to reach what Grunkle Stan called "the best campsite in Oregon." She was sitting in the back, occasionally looking longingly at Dipper's sleeping face in the rear-view

mirror. Shivers went down her spine as she took in his peaceful face. Every minute or two his mouth would twitch into a smile and his eyelids would flutter. She imagined being in bed with him next to her. She closed her eyes and manipulated her mental form into gently kissing his soft mouth and tousling his beautiful brown locks. The next thing she knew, she had woken up from a peaceful sleep to hear Grunkle Stan yelling at a fellow driver.

"Hey shit-for-brains! Where'd you learn to drive, a fucking mental asylum?!" the old man yelled while sticking his middle finger out the window. The other driver just kept going. "Kids, don't tell your parents I said that in front of you. They might get mad at me or something."

Mabel giggled, but the dream still lingered at the back of her mind. "Grunkle Stan! We're 14 now! Almost 15! It's okay."

"Yeah, well, not to your parents. It's like they're Mormon or some shit. It's ridiculous! When I was 14, I was out banging chicks twice my age. And you guys can't even cuss."

Mabel hadn't realized it, but Grunkle Stan's tirade had awoken Dipper.

"Huh? Where are we?" Dipper said, sitting up from where he had been leaning against the window in the passenger seat.

"Camping, remember?" Mabel said, still shaking the dream from her mind. She made eye contact with Dipper through the rear-view mirror and held his gaze for what seemed like an eternity. Grunkle Stan broke the gaze by jerking the wheel to the left, which slammed the twins into the side of their doors. With a screech, the car drove up the oncoming lane to pass a sluggish semi. Dipper and Mabel sat back in there seats, both thinking about the look they had shared through the cold glass of the mirror.


	6. Chapter 6

**Sorry this is short and has no action! Expect Chapter 7 in a few days to a week.**

The aging car skidded to a halt on the gravel surface of the campsite parking lot. The kids and Grunkle Stan opened the doors and got out to stretch, yawning, and in Mabel's case, chugging the remainder of the bottle of Mabel-Juice she had saved all the way from Piedmont.

"Okay kids, time to set up camp. Dipper, you get the bags out of the back. Mabel, you start setting up the tents," Grunkle Stan directed.

"Uh, Grunkle Stan, what are you going to do?" asked Dipper.

Grunkle Stan sat on a log and pulled a lukewarm Pitt Cola out of his pocket. "Watch you, of course! Not like there's any TV here."

Dipper and Mabel just sighed and got to work. Dipper had unloaded all but one of the bags and Mabel had set up two tents.

"Grunkle Stan? We only have two tents," Mabel said.

"I must have forgotten one," Grunkle Stan said a little suspiciously.

"Forgot?" Mabel asked.

"Fine, I sold it at a pawn shop," Grunkle Stan said. "Oh yeah, by the way, Dipper, I sold your hat collection for fifteen bucks. Here's your share," Stan said, throwing Dipper a five.

"You've got to be lying!" Dipper said. "The hat I got from Wendy was in there!"

"Alright kid, you got me. I actually sold it for twenty five, here's the rest of your cash." Stan threw another five at Dipper. Dipper just shook his head at the loss of all his favorite hats. Mabel, however, was ecstatic. She knew that with only two tents, somebody would have to buddy up. And she knew for a fact that Dipper wouldn't want to sleep with Grunkle Stan, which left just one option: her.

 _This is my chance to get close to Dipper!,_ she thought. Dipper finished unloading and put the bags along the inside walls of the two tents, and began to unroll the sleeping bags.

"All done!" Dipper called from inside the tent. He slowly backed out the tent flap and got up, wiping the dirt off his knees. "Want to get a campfire going?" he asked.

"Okay," Mabel replied, thinking about snuggling up to Dipper in front of the glowing flames. Mabel began to gather wood for the fire while Dipper rummaged around inside the tent to find lighter fluid and matches. He found what he was looking for and returned to the fire ring between the two tents, where Mabel was setting up the logs so that they were suitable for the fire. He saw she was struggling to get the tepee of wood to balance, so he took over while Mabel managed the matches.


	7. Chapter 7

**Dipper's POV:**

Dipper knew that Mabel was interested in him, and not just because he knew about the demon magic at play. He had noticed all the signs and clues. The awkwardness, how quickly she had closed the journal, the glance in the mirror. He smiled on the inside while he adjusted the firewood in the firepit. He finished stacking and stood up, dusting off his began to try and strike the match, but each time the match failed to light.

"Here, let me help," Dipper said, bending down behind Mabel and resting his head on Mabel's shoulder while his arms reached around her. His hands touched Mabel's cool skin as he grabbed her hands to guide her.

She started to tremble but quickly stopped, but not quick enough to escape Dipper's keen observation skills. He smiled as he guided Mabel's hands, allowing her to light the match and start the fire. Dipper and Mabel blushed and quickly got up and moved in order to sit on logs, on opposing sides of the campfire. Both were gleeful on the inside, but neither showed it.

Grunkle Stan looked concerned at their separation. "Did you kids fight or something?" he asked.

"No," both the twins replied.

"You guys want s'mores?"

"Of course!"

 **When** the marshmallows were all gone and the fire had begun to burn itself out, Grunkle Stan had said goodnight and gone to bed. The twins, who had not moved since they had sat down, could hear him in his tent snoring.

"Just so you know," Mabel tentatively began, but was silenced by Dipper.

"About what happened… by the fire. That didn't mean anything… did it?"

Mabel sighed and spoke quietly, almost whispering. "I'm not sure."


	8. Chapter 8

**ieatsmiledip here, sorry this took so long. Next chapter will be the actual lemon but I hope you enjoy the lead up I wrote!**

Dipper and Mabel got up and went to their shared tent. Dipper turned on a flashlight, which dimly illuminated the tent. They both turned away from each other and began to change, both peeking over their shoulders occasionally. Dipper took in Mabel's smooth, slightly tan skin and perky, B-cup breasts. Her rounded butt glowed in the light of the flashlight, and her hair formed an angelic halo around her head.

On the other side of the tent, Mabel was spying Dipper's toned muscles, which had formed over the last two years. His shaggy brown hair seemed to sparkle to the love-stricken Mabel. The moment ended when both twins finished pulling on their pajamas and got into their sleeping bags. They turned away from each other and lay, thinking. Five, ten, fifteen, twenty minutes passed before Mabel spoke.

"Dipper?"

"Yes Mabel?"

Mabel sighed tentatively. "I've made my decision."

"Mabel, I have something to say," Dipper said, sitting up in his sleeping bag.

"Dipper, wai-" Mabel began to say, but was interrupted by Dipper.

Dipper sighed sadly before beginning. "Mabel, I'm sorry about what happened. If you think it's wrong, or disgusting, I understand. But there's something about you that I just… can't seem to resist."

Mabel looked surprised. "Do you mean it Dipper?"

"Of course."

She blinked and sat up. "Dipper, I… feel the same. It's just… we can't."

"Why not?" Dipper said, getting a little heated. "If we feel this way, what's to stop us?" It's not like they could do anything."

 **Mabel's POV:**

Mabel smiled at Dipper's traditional determination. She thought about all the times Dipper had sacrificed to help her, and how little she had given in return. She decided that she would sacrifice for him. She was willing to lose everything. Friends, approval of their family, respectability.

She reached out and grabbed Dipper by his shoulders and pulled him in for a passionate kiss.

Mabel could feel Dipper still trying to talk into her lips. He stopped talking and froze as Mabel worked her lips against his. Dipper realized what was happening and reached behind Mabel to push her lips to his. He could smell the delicate strawberry scent of her hair and felt her soft lips against his as Mabel's mouth parted slightly, allowing tongues to enter the passionate fray. Dipper and Mabel began to crawl out of their sleeping bags and onto the open floor, in constant liplock. Mabel fell backwards on to her back with Dipper on top of her. They separated their mouths and gazed into each other's eyes, breathless.

"Dipper," Mabel said.

"Yes Mabes?"

"I think I'm ready for you."


	9. Chapter 9

**ieatsmiledip here! Sorry this chapter took so long, my life has been hell the last few months. Expect the next part within a week or two, it'll be pretty short but hey, something is something right? Thanks for reading!**

"Are you sure about this?" Dipper asked.

"Of course, DipDip. I love you."

Dipper smiled. He got off of Mabel and pulled his shirt off, while Mabel also began to undress. She unbuckled her bra and cast it aside, giving Dipper full view of her breasts. Dipper was now in only his underwear, his erection creating a tent in his boxers.

Mabel blushed. "Do you like them?"

Dipper smiled. "I like everything about you."

Mabel giggled and reached over. With a swish she pulled down Dipper's boxers. His erection sprung free, suprising Mabel with it's length. Her surprise, however, faded quickly. She kneeled down and grabbed his shaft, gently stroking it. Dipper moaned at her gentle touch.

She leaned forwards and took him into her mouth, rolling his head with her tongue. She took him deeper, and his six incher brushed the back of her throat. She began to gag, but managed to hold it back.

Dipper looked down at Mabel. "Where'd you learn to give head so well? I thought you were a virgin," he said, smirking a little.

Mabel rolled her eyes. "I don't tell you everything I do."

Even though Mabel had never actually gone farther than a blowjob, she loved feeling experienced in front of Dipper. She pushed Dipper over until he was laying down on one of the discarded sleeping bags. She clambered forwards and pushed Dipper's penis against the entrance to her vagina. She pinned down Dipper's arms and kissed him lightly, looking right into his eyes.

"I hope your 'Dipstick' fits, Dipper," Mabel said in her best "sexy knockout" voice.

"Why thank you madáme Mabel," Dipper replied in an equally ridiculous French accent.

Mabel rolled her eyes and lowered her right arm until she wrapped her hand around Dipper's throbbing erection. She gave out a slight shiver and moan as she lowered herself onto it, her dripping wet vagina stretching around Dipper's six inch penis. She felt a brief flash of pain as her hymen broke, but it didn't bleed. Mabel was relieved, as she didn't want her brother to think that she was still a virgin. Dipper moaned as Mabel managed to take all of him inside of her.

"I love you Dipper."

"I love you too Mabel."

Mabel began to rock quicker and quicker on Dipper's 'dipstick'. She started to feel herself reaching the edge of pure pleasure. Her rocking and bouncing became sloppier, her breath more ragged. She stopped moving and shuddered, waves of ecstasy racing through her body. Dipper just lay on the sleeping bag, panting. As Mabel bounced one final time on Dipper, he moaned and came deep inside of Mabel.

 _Is that what sex feels like? I should have started years earlier!_ Mabel thought, her face flushed. She pulled herself forwards and watched as Dipper's now flaccid penis slid out of her, followed by what looked like a gallon of semen.

She layed down next to Dipper, snuggling up against his warm body. They looked into eachother's eyes peacefully. Both of the twins began to drift off to sleep.

"Oh my god!" Dipper whispered yelled, waking up Mabel.

"What is it?" she asked.

"I didn't wear a condom!"

"Don't worry, I'm on my birth control pill."

Dipper smiled, at peace. Mabel giggled softly, and the twins drifted off to sleep.


End file.
